This paper describes the state of the art in applications ofvoice-processing technologies. In the first part, technologies concerning the implementation of speech recognition and synthesis algorithms are described. Hardware technologies such as microprocessors and DSPs (digital signal processors) are discussed. Software development environment, which is a key technology in developing applications software, ranging from DSP software to support software also is described. In the second part, the state of the art of algorithms from the standpoint of applications is discussed.Several issues concerning evaluation of speech recognition/ synthesis algorithms are covered, as well as issues concerning the robustness of algorithms in adverse conditions.Recently, voice-processing technology has been greatly improved. There is a large gap between the present voiceprocessing technology and that of 10 years ago. The speech recognition and synthesis market, however, has lagged far behind technological progress. This paper describes the state of the art in voice-processing technology applications and points out several problems concerning market growth that need to be solved.Technologies related to applications can be divided into two categories. One is system technologies and the other is speech recognition and synthesis algorithms.Hardware and software technologies are the main topics for system development. Hardware technologies are very important because any speech algorithm is destined for implementation on hardware. Technology in this area is advancing quickly. Almost all speech recognition/synthesis algorithms can be used with a microprocessor and several DSPs. With the progress of device technology and parallel architecture, hardware technology will continue to improve and will be able to cope with the huge number of calculations demanded by improved algorithms of the future. Also, software technologies are an important factor, as algorithms and application procedures should be implemented by the use of software technology. In this paper, therefore, software technology will be treated as an application development tool. Along with the growth areas of application of voice-processing technology, various architectures and tools that support applications development have been devised. Also, when speech processing is the application target, it is important to keep in mind the characteristics peculiar to speech. Speech communication basically is of a nature that it should work in a real-time interactive mode. Computer systems that handle speech communications with users should have an ability to cope with these operations. Several issues concerning real-time interactive communication will be described.For algorithms there are two important issues concerning application. One is the evaluation of algorithms, and the other is the robustness of algorithms under adverse conditions. Evaluation of speech recognition and synthesis algorithms has been one of the main topics in the research area. However, to consider applicatio...